Radio receiving set



July 21, 19429 G. B. KNbs 72,290,644

RADIO RECEIVING SET Filed June 2 1, 1939 INVENTOR. Gil/W4? 5026i k/WJ. BY "WK ATTORNEY.

Patented July 21, 1942 RADIO RECEIVING SET Gunnar Borge Knos, Eindhoven, Netherlands, as-

signor, by mesne assi gnments, to Radio Corporation of America, New York, N. Y., a corporation of Delaware Application June 24, 1939, Serial No. 281,021

In the Netherlands June 8, 1938 4 Claims. (Cl. 74-10) This invention relates to a radio apparatus which, by means of a station selector consisting of a keyboard, a selecting disc and associated mechanism, can be automatically tuned to a number of stations, This apparatus is characterized in that the motion of the keys is transmitted, through a spring which is itself moved from its position of rest by this movement, to the movable condenser shaft whose movement is braked by a damper.

In sets of the above type hitherto known the movement of the keys is transmitted either directly or through gearing to the movable condenser shaft. This arrangement has the drawback that if the keys are4too strongly pressed there is a risk of damaging the movable condenser part. Furthermore, this comparatively delicate part of the apparatus then experiences also strong shocks. All these drawbacks are avoided by the construction according to the present invention. Of course, this construction can be used both for rotating plate condensers and slide condensers. In a suitable form of construction the spring transmitting the movement possesses a preliminary tension in its position of rest, and an abutment stop assures the correct relative position of the members connected by the spring.

The invention will be more clearly understood by reference to the accompanying drawing wherein Fig. 1 illustrates diagrammatically the application of the improved push button mechanism to a receiver provided with a condenser of the rotary type; Fig. 1a is an enlarged view of a portion of Fig. 1 showing the push buttons and the parts associated therewith; and Fig. 2 illustrates the invention applied to a condenser of the slidable electrode type.

Fig. 1 shows one form of construction of the condenser part of the radio set according to the invention, in which the tuning condenser is constructed as a rotating plate condenser. The condenser shaft is denoted by I, whereas the rotary part of the condenser is designated by 2. A pinion 3 is provided on the shaft I This pinion meshes with a toothed sector 4 mounted on the shaft 5. The member 6, which cooperates with the keys 1 having different active lengths, is movable about the shaft 5. The member 6 is connected to the toothed sector 4 through the intermediary of the retracting spring 8. In fact, this spring is connected at A to the member 6 and secured at B to the projecting part 9 which is rigidly connected to the sector 4. The projecting part 9 is provided with the stop H] which by engaging member the spring 8 the correct position of the keys I and the member 6 on the one hand and of the rotary part 2 of the condenser on the other hand is always assured. Furthermore, the toothed sector 4 has pivoted to it the rod H which carries the piston l2 of the air-damper l3. The housing of the latter is furnished with. a small aperture l4. Upon a movement of the toothed sector 4 the piston l2 moves inside the housing of the damper so that air is compressed into the lower part of the housing and then forced out therefrom through the aperture l4. Since the aperture l4 through which this must be effected is made very small the piston l2 canmove only at a very slight speed inside the housing of the damper, so that the toothed sector rigidly connected to the piston l2 (and consequently also the movable condenser part 2) can only acquire a very low angular speed. Thus, independently of the speed at which the keys are pressed the movable condenser part is shifted at a very low speed so that there is no risk of damaging this part.

In the constructions hitherto used the member 6, which may have various forms and may, for instance, consist of a plurality of separate parts, is rigidly connected to the toothed sector 4, so that a movement of the stop is directly transmitted to the sector. Consequently, this is not the case according to the invention. Upon pressing one of the keys 1 which pass through suitable apertures in a support 1a the member 6 will immediately turn through a definite angle, it is true, but the sector will not immediately but only gradually follow this movement due to the presence of the spring 8 and the damper l3. In 'fact, upon turning the member 5 the spring 8 is stressed so that the member 6 is set free from the stop H). The sector 4 will not be able immediately to obey the force exerted on it by the spring 8 due to the operation of the damper I3, since the piston l2 will have to force the air only come to a standstill when the spring 8 has of which is well known. Suitable latching devices are shown in the patents to Long 1,945,557 and Hammond 2,052,708. By pressing another key the first pressed key is released, a spring such as forcing the released key to normal position. A spring l5 acting on the condenser shaft will act on the shaft to cause it to resume its initial position, during which movement the shaft through the gears 3 and 4 perience the braking action of the damper i3.

In the construction shown in Fig. 2 the tuning condenser is a three-part slide condenser. The three movable parts I6 are mounted on a common shaft I! which is slidably journalled. The stator parts of the condenser are designated by Hi. The keys l9 having relatively difierent active lengths act on a pressing plate 20 which through the intermediary of a spring 21 acts on the shaft l1. At the end of the shaft I1 is provided a damper 22. The operation of the device is principally similar to that of the device shown in Fig. 1. The spring 23 causes the condenser shaft to resume its zero position upon the return of a pressed key from its latched pressed position. Both upon pressing a key and upon releasing of the spring 2| incooperation with the damping device the shaft of the condenser is caused to execute a retarded movement.

I claim:

1. In a mechanism for positioning an adjustable control device a displaceable driven means for operating said device, an adjustable control device determining the positioning of said driven means, a plurality of independently operable position selectors each acting upon operation to effect the adjustment of said control device to a position which corresponds to a desired position of said driven means, resilient driving means for said driven means and including a spring element connecting said driven means to said adjustable control device, said resilient driving means acting to follow up any adjustment of said control device with a movement of said will again exdriven means to a position determined by the position to which the control device is adjusted.

2. In a mechanism for positioning an adjustable control device, means including a control shaft for operating said device, an adjustable stopping element for determining the positioning of said control shaft, a plurality of selectively operable means each acting upon operation to effect the movement of said stopping element to a predetermined position, a driving element for said first named means, an energy storing device providing a driving connection between the stopping element and the driving element, said energy storing device acting in conjunction with and. upon operation of the stopping element to one of said positions, to drive said driving element to a position corresponding to the position of the stopping element thereby effecting the adjustment of said adjustable control device to a predetermined position.

3. The arrangement described in claim 2 characterized by that each of said selectively operable means comprises a member adjustable with respect to said adjustable control element whereby each desired position on said adjustable control element may be adjustably predetermined.

4. In a mechanism for positioning an adjustable control device, a driven element operatively connected to said control device for operating said control device, a movable stop for limiting the movement of said driven element, a plurality of selectively operable means each acting upon operation to effect the movement of said stop to a desired position, resilient driving means for coupling said driven element to said movable stop, said resilient driving means acting to follow up any change in the position of said stop with a movement of said driven element which brings said driven element against said stop, and means for preventing rapid movements of said driven element. A

GUNNAR BORGE KNOS. 

